1. Field of the Invention
Embodiments of the present invention relate generally to building construction using masonry and mortar, and, more specifically, to techniques for wicking moisture out of the mortar.
2. Description of Related Art
Masonry (e.g., stone, bricks, or concrete masonry units) is a reservoir material, absorbing water and retaining it in its porous structure. To counteract this, construction practices have moved towards allowing for small openings on the bottom of the wall, as shown in FIGS. 1 through 4, to create a ventilated cavity behind the masonry veneer. Often this cavity, usually less then 2 inches wide, is blocked by residual mortar fallen during construction, and the small vents can be blocked by dirt and pests. Not allowing water to escape can cause pressure build up behind the wall, causing bricks to spall. Excess moisture can cause condensation in both the masonry and the wall cavity causing mold, structural, and cosmetic damage.
Water can move through bricks via capillary action and its inherent porous nature. However, mortar does not have these same abilities, and water often relies on cracks in the mortar to pass through. The mortar used today is made from lime, cement, and sand, which dries into a very rigid mixture, unlike the lime putty and sand used before 1930. The new type of mortar does not expand and contract with moisture increase and temperature change like its pre-1930s counterpart. Instead, the moisture retained in the mortar goes through a freeze thaw cycle in which the frozen water expands, causing movement and cracking in the mortar over time.